I guess I burn the extract a little when I added it. What should I do? There are some black flakes in the boil. If I strain them out, won't I lose some of the hops too? And therefore the flavor? Any suggestions? Thanks...

first recipe i ever did i burned the extract a little because i never pulled it off the burner as i added it. Just leave it be. The solids will precipitate out when you put it into primary. secondary fermentation if you decide to take it into secondary will take care of the rest. I did notice a little carmel/burnt taste but it was very subtle and ended up ok in the end.

LME is definitely easier to burn than DME because it sinks right to the bottom. As others mentioned get the pot off the heat during malt addition. What I like to do is keep my large stirring spoon under the flow of the extract as I add to the pot. Most of it sticks to the spoon and allows me to stir it in while keeping most off the bottom. After you have added the extract, stir it until fully dissolved. Then stir it for another minute. You'd be surprised if you scrape your spoon against the bottom that you will pick up some "sludge" which is settled extract even if you think it's fully dissolved (LME talking about here).

What happens is the LME is so dense it falls to the bottom and then quickly cools the surrounding water. While the temp of the water is close to boiling at the surface/middle, at the bottom it's normally much cooler and dissolving takes a much longer time. If you put the pot back on the burner before this is completely dissolved it will very quickly scorch. This is why I like to use a pot that doesn't have a non-stick layer (or that I care about scratching), since I like to physically scrape along the bottom and check the spoon for undissolved LME. If you do that and can be sure there is none left sitting on the bottom you will never have to worry about scorching.